Another speed increase

Prior to April my speeds were 6350 ish and constant at that most of the time. Then in April they rose to 6550 ish and stayed more or less around there. This was discussed here. Now this morning I got 6741 and a moment ago 6697. Looks like the network just got faster...Plusnet or TBB?

Examples of the changes:

...while my sig shows the fastest yet. Not massive changes, but that's a 5.7% increase in three months for no changes at my end, and no notice of changes from Plusnet. Who turned up the speed? More network changes?